Redesign derive_component to cgp_component with improved syntax

[soareschen]

Closes: #25

• Rename the attribute #[derive_component] to #[cgp_component]
• The macro syntax has been changed as follows:
  • Old: #[derive_component(NameGetterComponent, NameGetter<MyContext>)]
  • New: #[cgp_component { name: NameGetterComponent, context: MyContext, provider: NameGetter }]
• For migration, the following regex can be used in a global search and replace:
  • Search: #\[derive_component\(([\w<>, ]+), (\w+)<(\w+)>\)\]
  • Replace: #[cgp_component {\n name: $1,\n provider: $2,\n context: $3,\n}]